CA3130343A1 - Method for preparing a heat-modified starch - Google Patents

Abstract

The invention relates to a method for producing a heat-modified starch, comprising the steps consisting in: (i) preparing a starch milk having a solids content of between 30 and 40%, preferably between 35 and 37% by weight, (ii) adding a solution of an alkaline agent at a weight concentration of between 25 and 35%, preferably of 30%, so as to obtain a conductivity on the milk of between 4 and 7 mS/cm, (iii) ensuring a contact time of between 0.5 and 2 hours, (iv) filtering and drying the starch milk such that the conductivity of the dried starch resuspended at 20% by weight of solids is between 0.7 and 2.5 mS/cm, (v) heating said dried starch so as to bring it to a temperature of more than 180°C for a residence time of between 10 and 40 minutes, even more preferentially between 15 and 35 minutes.

Description

Description Title: Process for preparing a starch thermally modified The invention relates to the production of thermally modified starch, starch whose viscosity is stabilized following this heat treatment. Of such thermally modified starches then find use as agents texturizers and thickeners in many food applications, especially in soups, sauces, in desserts such as yoghurts, stirred fermented milks, thermized yogurts, dessert creams, but also drinks, prepared meals, meat or fish preparations, Phone than surimi.
The invention also relates to the use of these starches thermally modified, in combination with dextrins, as a coating agent for the preparation of transparent coating of vegetables (potato fries), of meat products or even pasta for pizzas, donuts or pie bases, snacks, croquettes, cereals or breading agents.
Background of the invention

[0002] Biochemically synthesized, source of carbohydrates, starch is one of the most widespread organic materials in the plant world, where it constitutes the nutritional reserve of organisms.

[0003] Starches have always been used in industry.
food, no only as a nutritious ingredient but also for their properties technological, as a thickening agent, binder, stabilizer or gelling agent.

[0004] For example, native starches are used in preparations requiring cooking. Corn starch, in particular, is the basis of custard powders.

Since it is rich in amylose, it retrogrades and therefore strongly gels.
He allows to obtain firm blanks after baking and cooling. He agrees also for pastry creams.

[0006] But these cannot be used in pastries intended for to be frozen because, on defrosting, the phenomenon of syneresis, which results in through an expulsion of water, destroys the texture of the cream.

[0007] Thus, in the native state, the starch is of limited application due to the syneresis, but also because of:
- its low resistance to shear stresses and treatments thermal, - its low processability and - its low solubility in common organic solvents.

[0008] Therefore, to meet demanding technological needs today, the properties of starch must be optimized by various so-called modification methods.

[0009] These main modifications are then aimed at adapting the starch to technological constraints resulting from cooking, but also from freezing / thawing, canning or sterilization, and to return compatible with modern food (microwaves, preparations instantaneous, "high temperatures" ...).

The modification of the starch then aims to correct one or some of the faults mentioned above, thus improving its versatility and satisfying the consumer demand.

The starch modification techniques have been generally classified into four categories: physical, chemical, enzymatic and genetic, the purpose being to produce various derivatives with physicochemical properties optimized.

The chemical and physical modifications are those most often implemented.

The chemical treatment consists in introducing functional groups in starch, which remarkably alters its physicochemical properties.

Such modifications of native granular starches indeed alter deeply the behavior in gelatinization, sticking and retrogradation.

Generally, these modifications are carried out by derivatization chemical, such as esterification, etherification, crosslinking or grafting.

However, chemical modifications are less sought after by the consumer in food applications (also for reasons environment), although some changes are considered sure.

Various physical modifications are therefore proposed, by example :
- treatment by moist heat (Anglo-Saxon term for Heat Moisture Treatment or HMT), consisting of treating starch to moisture levels controlled (22-27%) and at high temperature, for 16 hours, in order to alter the structure and physicochemical properties of starch;
- annealing (English term for annealing), consisting in treating starch in excess of water, at temperatures below the temperature of gelatinization, in order to approach the glass transition temperature;
- ultra high pressure treatment (Anglo-Saxon term for High Pressure Processing or HPP), by which the amorphous regions of the granule are hydrated starch, which leads to distortion of the crystalline parts of the granule and promotes the accessibility of said crystalline regions to water;
- the glow discharge plasma treatment, which generates, at temperature ambient, high-energy electrons and other highly active species.

Applied to starch, these active species excite the chemical groups of starch and cause significant crosslinking of macromolecules;
- osmotic pressure treatment (acronym OPT), executed in the presence of solutions with a high salt content. The starch is suspended in sodium sulfate to produce a uniform suspension.
The starch changes from type B to type A after processing, thus acquiring a gelatinization temperature which increases significantly;
- treatment by thermal inhibition. In general, inhibition thermal means the dehydration of a starch until it reaches the state anhydrous or substantially anhydrous (ie <1% moisture), then a processing thermal at over 100 C for a period of time sufficient to inhibit starch, in this case here to give it properties starches crosslinked. It is also necessary to place the starch in conditions of pH at least neutral to preferably alkaline before proceeding to the step of severe dehydration.
An alternative treatment by thermal inhibition has been proposed in phase solvent, which consists of heating a non-pregelatinized granular starch to environment alcoholic, in the presence of a base and salts, at a temperature of 1200 to 200 C, for 5 minutes to 2 hours.

Anyway, the thermal inhibition process then leads to obtain a starch paste exhibiting properties of increased resistance to viscosity breakage, and a non-cohesive texture.

The technical field to which the invention relates is that of treatment by thermal inhibition of starch, without hydro-alcoholic.

In this particular technical field, we can cite more particularly US 6.221.420 which describes a thermally inhibited starch, obtained by dehydration then heat treatment.
The main stages are:
- starch dehydration to a water content of less than 1`) / 0 carried out at a temperature between 100 and 125 C, then - the heat treatment of the dry starch thus obtained, at approximately 140 C, in a bed fluidized reaction, for a period of the order of 20 hours.

Preferably, before the starch dehydration step, he it is recommended to carry out a starch alkalinization step, allowing to bring the pH of the starch suspension to a value between 7 and 10, of preferably between 8 and 10.

At this stage, before the actual dehydration step which precedes the inhibition step, the water content of the starch (as exemplified) is so between 8 and 10%.

US 2001/0017133 describes a similar process, in which the starch is also dehydrated below 125 C before the inhibition process is not started (at a temperature of more than 100 C, preferably understood between 120 and 180 C, more preferably between 140 and 160 C) during a duration of up to 20 hours, preferably between 3 hours 30 and hours 30.

Before the dehydration step, the conventional alkalization step led 5 to a starch suspension having a pH value between 7.5 and 11.2, preferably between 8 and 9.5%, and a water content of Between 2 and 15%.

A variant has been proposed in patent application WO 2014/042537, variant which involves heating an alkaline starch to temperatures between 140 and 190 C, ensuring that the inhibition process be initiated and carried out in the presence of water in sufficient quantity, ie more than 1% of water.

In other words, this method recommends thermally inhibiting a starch previously alkalized without proceeding to a dehydration step.

The starch preparation or starch is thus brought to a pH of between 9.1 and 11.2, preferably at a value of the order of 10, and humidity is adjusted between 2 and 22%, preferably between 5 and 10%.

Thermal inhibition is then performed directly on this powder or this starch, at a temperature between 140 and 190 C, preferably between 140 and 180 C, for a period of 30 minutes.

From all of the above, it can be seen that the inhibition methods heat used to stabilize the viscosity of the starches use Game processes require:
- the implementation of long durations of treatment, ie up to 20 hours, and - control of the water content of the starches to be treated, depending on the processes offered in the state of the art, whether at values of less than 1% or at conversely between 2 and 22%.

[0029] There therefore remains a need for an original process.
inhibition starch, allowing the reaction time to be further reduced, and without born it is necessary to control the water content of the starch to be inhibited thermally.

Description of the invention

[0030] Thus, the invention relates to a process for producing a starch thermally modified from a starch milk comprising the steps consists in :
(i) prepare a starch milk having a dry matter of between 30 and 40%, preferably between 35 and 37% by weight, (ii) add a solution of an alkaline agent to a mass concentration included between 25 and 35%, preferably 30% so as to obtain a conductivity on milk between 4 and 7 mS / cm, (iii) ensure a contact time of between 0.5 and 2 hours, (iv) filter and dry the starch milk so that the conductivity of starch dried and resuspended at 20% dry matter is included between 0.7 and 2.5 mS / cm, (y) heating said dried starch so as to bring it to a temperature of more at 180 C for a residence time of 10 to 40 minutes, plus more preferably between 15 and 35 minutes.

The starch to be used in the process of the invention can be of any origin, e.g. maize, waxy maize, amylomai, wheat, waxy wheat, legumes such as peas and field beans, potatoes, potatoes earth waxy, tapioca, tapioca waxy, rice, konjac, etc.

By bean is meant the group of annual plants of the species Vicia faba, belonging to the group of legumes of the family Fabaceae, subfamily of Faboideae, tribe of Fabeae. We distinguish the Minor and Major varieties. In the present invention, the wild and those obtained by genetic engineering or variety selection are all excellent sources.

Preferably, we will choose corn starch, more particularly waxy corn starch (high in amylopectin), the potato starch, cassava, peas and field beans, as it will be exemplified below.

The alkaline agent is preferably chosen from the group consisting of of sodium hydroxide, sodium carbonate, tetrasodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, phosphate trisodium, calcium carbonate, calcium hydroxide, calcium carbonate potassium, and potassium hydroxide taken alone or in combination, plus more preferably sodium carbonate.

The method according to the invention firstly requires the preparation a starch milk with a dry matter of between 30 and 40%, of preference between 35 and 37% by weight. As will be exemplified below, the dry matter is set at 36.5% by weight.

The next step then consists in controlling the alkaline impregnation of starch by adding the alkaline agent as a solution to a concentration mass between 25 and 35%, preferably 30% to obtain a conductivity, on milk, between 4 and 7 mS / cm.

[0037] The Applicant company has in fact found that:
- the addition of the alkaline agent, more particularly sodium carbonate directly on the starch in the milk phase makes it possible to achieve more efficiently the high pH values sought (are between 10.2 and 10.8, preferably between 10.5 and 10.65) than a spray of sodium carbonate on starch in the dry phase, in the sense that the addition in the milk phase allows a better migration of carbonate inside starch granules compared to a powder impregnation.
Moreover, as the powder phase impregnation requires adjusting humidity starch at high values, part of the energy dedicated to treatment of product will therefore be lost to ensure the evaporation of residual water.
- adding the alkaline agent in solution from a solution to a concentration mass of between 25 and 35%, preferably 30%, allows a total dissolution of the alkaline agent in starch milk, an adjustment of pH plus faster and finer, and to avoid a deposit of solid alkaline agent in the bottom of reactor in the event of non-solubilization.
The most important technical effect here is to bring a contact time understood between 0.5 and 2 hours.

- control of the starch impregnation level via measurements of conductivity makes it possible to achieve the precision required for said high pH values.

The next step leads to filtering and drying the starch milk of way to this that the conductivity of dried and resuspended starch at 20% matter dry is between 0.7 and 2.5 mS / cm.

The last step is to heat the dry starch thus obtained from so as to bring it to a temperature of over 180 C for a period of stay between 10 and 40 minutes, more preferably still between 15 and 35 minutes.
The rise in temperature during step (y) of the dry starch obtained in step (iv) is preferably carried out in devices of the turbojet type continuous, for which the setpoint temperature is set at more than 190 C, of preferably between 195 and 240 C, and the delta T, defined as the difference temperature between the setpoint temperature and the product temperature in output of the reactor, is between 15 and 25 C.

The invention also relates to a thermally modified starch obtainable according to the process described above.

The thermally modified starches according to the invention will be advantageously used, depending on their respective properties, as as a thickening agent or texturizing agent in food applications, especially in soups, sauces, drinks and prepared meals and in desserts such as yoghurt and stirred fermented milk and yoghurt thermized.

By their texturing and gelling properties, they will find also from numerous applications in fields as varied as:
- sour sauces and soups (pasteurized and sterilized), - pasta sauces with meat juice, - desserts such as yoghurts, fruit preparations for yoghurts, milks brewed fermented foods, thermized yogurts, dessert creams, - hot mayonnaise and vinaigrette, - pie filling, fruit or stable meat or meat filling and sweet or savory, dinners (cooked dishes with a short shelf life), - pudding (dry mixture to cook), - baby jars / infant formula, - drinks, - prepared meals, preparations based on meat or fish, such as surimi.
- Food for animals - preparation of transparent coating of vegetables, such as for example from potato fries, meat products or even pasta for pizzas, donuts or pie bases, snacks, croquettes, cereals or breading agents.
For the latter application, these coatings (Anglo-Saxon technical term of coatings) or transparent coating (English technical term for clearcoating) are designed to improve shelf life and crispness fries after cooking.
Conventional coating recipes include a plurality of constituents more or less complex, in particular:
- flour, especially rice - a chemically modified starch of the highly crosslinked starch type phosphate (crosslinking agent: sodium trimetaphosphate) of degree of substitution of 0.4% maximum - a native starch - a dextrin.
A recipe such as the one proposed by the company can be chosen.
Applicant in its patent EP 1,557,093, where these chemically modified starch components, native starch and dextrin come from legumes, especially peas.

The invention will be better understood with the aid of the following examples, which are intended to be illustrative and not limiting.
Material and methods

Conductivity measurement The method implemented here is adapted from the European Pharmacopoeia ¨
official edition in force ¨ Conductivity (2.2.38).
Materials:
KNICK 703 electronic conductivity meter also equipped with its measured and checked according to the procedure described in the manual of instructions which relates to it.
Operating mode:

A solution is prepared containing 20 g of sample in powder form and g of distilled water having a resistivity greater than 500,000 ohms.cm.
The measurement is carried out at 20 C using the conductivity meter referring to the operating mode indicated in the user manual of the device.
5 Values are expressed in microSiemens / cm (pS / cm) or miliSiemens / cm (mS / cm).

Measuring the viscosity of a starch suspension using the Rapid Viscosimeter Analyzer (R VA) This measurement is carried out at acidic pH (between 2.5 and 3.5) under conditions of 10 concentrations determined and according to a temperature / time analysis profile adapted.
Two buffer solutions are prepared:
Buffer A
In a 1 liter beaker, containing 500 ml of demineralized water, add - 91.0 g of citric acid monohydrate (purity> 99.5%) and homogenized, - 33.0 g of sodium chloride (purity> 99.5%), and homogenizes until complete dissolution, -300.0 g of 1N soda.
It is transferred to a volumetric flask of 1 L and completed with water demineralized at 1 L.
Buffer B
100 g of Buffer A are mixed with 334.0 g of deionized water.

The product to be analyzed is prepared as follows:
A mass of 1.37 g of the dry product to be analyzed thus obtained is introduced directly into the bowl of the viscometer, and the Buffer solution is introduced B
until a mass equal to 28.00 0.01 g is obtained. We homogenize blade of the Rapid Visco Analyzer (RVA-NewPort Scientific).
The time / temperature and speed analysis profile in the RVA is then executed as following :

[0047] [Table 1]
Time Temperature Rotation speed hh: mm: ss C Revolutions / min (RPM) 00:00:00 50 100 00:00:10 50 500 00:00:20 50 960 00:00:30 50 160 00:01:00 50 160 00:05:00 92 160 00:17:00 92 160 00:20:00 50 160

[0048] End of test: 00:20:05 (hh: mm: ss) Initial temperature: 50 C 0.5 C
Data acquisition interval: 2 seconds Sensitivity: low (low)

The results of the measurements are given in RVU (unit used for express the viscosity obtained on the RVA), knowing that 1 unit RVU = 12 cPoises (cP).
As a reminder, 1 cP = 1 mPa.s.
The results will therefore be presented in mPa.s.
The measurements will be of viscosity at peak, ie viscosity value maximum between 4 and 6 minutes, and at the fall, i.e. the difference between the value peak viscosity and that measured at 17 minutes.
Examples

Example 1: Preparation of thermally modified starches A to from waxy corn starch.
1) The alkalization of waxy corn starch is carried out according to the stages following:
- Prepare a waxy corn starch milk at 36.5% by weight of dry matter (MS) - Prepare a sodium carbonate solution at 30% mass concentration and heat to 40-50 C to promote dissolution of the carbonate;
- Add the sodium carbonate solution at 30% concentration mass of so as to obtain a conductivity on the milk of between 4 and 7 mS / cm;
- Ensure a contact time of 0.5h;
- Filter and dry the starch so that the final conductivity on the powder resuspension at 20% by weight of DM, ie 1.9 mS / cm.
2) Heat treatment The product thus obtained is heat treated in turbojets continuous of the VOMM type as standard, the set point temperature of which is set at 200 C and configured to subject the product to a residence time of 20 min, and manner that the temperature difference between the setpoint and the temperature of the product at the outlet of the reactor, called Delta T, i.e. with a value of the order of 17 C.
Process parameters [Table 2]
Conductivity on product after Moisture impregnation before product Delta TTC setpoint Exp given at 20% in treatment stay (min) thermal MS weight in%
mS / cm A 1.9 11.8 17 200 20 The RVA viscosity measurements are carried out and are presented in the table below.
Results [Table 3]
RVA Peak Exp RVA Fall (mPa. $) (mPa. $)

Example 2: Preparation of thermally modified starches C to from waxy corn starch.
1) The alkalization of waxy corn starch is carried out according to the stages following:
- Prepare a waxy corn starch milk at 36.5% by weight of dry matter (MS) - Prepare a sodium carbonate solution at 30% concentration mass and heat to 40-50 C to promote dissolution of the carbonate;
- Add the sodium carbonate solution at 30% concentration mass of so as to obtain a conductivity on the milk of between 4 and 7 mS / cm;
- Ensure a contact time of 0.5h;
- Filter and dry the starch so that the final conductivity on the powder resuspension at 20% by weight of DM, i.e. 1.4 mS / cm 2) Heat treatment The product thus obtained is heat treated in turbojets continuous of the VOMM type as standard, the set point temperature of which is set at 200 C and configured to subject the product to a residence time of 25 min, and manner that the temperature difference between the setpoint and the temperature of the product at the outlet of the reactor, called Delta T, i.e. with a value of the order of 23 C.
Process parameters [Table 4]
Conductivity on product after Moisture impregnation before product Delta TTC setpoint Exp given at 20% in treatment stay (min) thermal MS weight in%
mS / cm 1.4 11.6 23,200 25 The RVA viscosity measurements are carried out and are presented in the table this-below.
Results [Table 5]
RVA Peak Exp RVA Fall (mPa. $) (mPa. $)

Example 3: Preparation of thermally modified starches G to from pea starch.
1) The alkalinization of pea starch is carried out according to the following steps :
- Prepare a pea starch milk at 33% by weight of dry matter (DM) - Prepare a sodium carbonate solution at 30% concentration mass and heat to 40-50 C to promote dissolution of the carbonate;
- Add the sodium carbonate solution at 30% concentration mass of so as to obtain a conductivity on the milk of between 4 and 6 mS / cm;
- Ensure a contact time of 0.5h;
- Filter and dry the starch so that the final conductivity on the powder resuspension at 20% by weight of DM, i.e. 0.9 mS / cm 2) Heat treatment The product thus obtained is heat treated in turbojets continuous of the VOMM type as standard, the set point temperature of which is set at 200 C and configured to subject the product to a residence time of 20 min, and manner that the temperature difference between the setpoint and the temperature of the product at the outlet of the reactor, called Delta T, i.e. with a value of the order of vs.
15 Process parameters [Table 6]
Conductivity on product after Moisture impregnation before product Delta TTC setpoint Exp given at 20% in treatment stay (min) thermal MS weight in%
mS / cm G 0.9 10.5 20 200 20 The RVA viscosity measurements are carried out and are presented in the table below.
Results 20 [Table 7]
RVA Peak Exp RVA Fall (mPa. $) (mPa. $)

Example 4: Preparation of thermally modified starches H-1 and H-2 from bean starch.
1) The alkalinization of the bean starch is carried out according to the stages following:
- Prepare a bean starch milk at 33% by weight of dry matter (MS);
- Prepare a sodium carbonate solution at 30% mass concentration and heat to 40-50 C to promote dissolution of the carbonate;
- Add the sodium carbonate solution at 30% by weight of concentration mass to the starch milk, so as to obtain a conductivity on the milk between 4 and 6 mS / cm;
5 - Ensure a contact time of 0.5h;
- Filter and dry the starch so that the final conductivity on the powder resuspension at 20% by weight of DM is between 1.5 and 2mS
2) Heat treatment The product thus obtained is heat treated in turbojets continuous 10 of the VOMM type in series, the set point temperature of which is fixed at 210 C and configured to subject the product to a residence time of the order of 13 ¨
25 min, and so that the temperature difference between the setpoint and the temperature of the product at the outlet of the reactor, called Delta T, i.e.
of a value of around 21-25 C.
15 Process parameters [Table 8]
Conductivity on product Humidity after product before TC impregnation Delta T treatment exp returned to stay locker (min) thermal suspension a in %
20% by weight MS in mS / cm Based starch of 0.133 8 0 0 0 faba bean H-1 1.9 14 24 210 13 H-2 1.9 14 23.5 210 25 The RVA viscosity measurements are carried out and are presented in the table below.
Results:
[Table 9]
Tests RVA Drop (mPa. $) RVA Peak (mPa. $) Bean starch base 82 323 Thermally modified starches prepared from H-1 bean starch and H-2 exhibit improved stability during the process of use by report with native starch: less phenomena of viscosity setting and demotion are observed when using these thermally modified starches.

Example 5: Preparation of thermally modified starches 1-1 and 1-2 from potato starch 1) The alkalization of potato starch is carried out according to the steps following:
-Prepare a potato starch milk at 36.5% by weight of matter dried (MS) -Prepare a sodium carbonate solution at 30% mass concentration so as to obtain a conductivity on the milk of between 4 and 7 mS / cm.
-Ensure a contact time of 0.5h -Filter and dry the potato starch so that the conductivity final on the powder resuspended at 20% by weight of DM, i.e. 1.1mS
2) Heat treatment The product thus obtained is heat treated in turbojets continuous of the VOMM type in series, the set point temperature of which is fixed at 210 C and configured to subject the product to a residence time of the order of 30 to 48min, and so that the temperature difference between the setpoint and the temperature of the product at the outlet of the reactor, called Delta T, i.e.
of a value of around 19-21 C.
Process parameters [Table 10]
Conductivity on product Humidity after product before TC impregnation Delta T treatment exp returned to stay locker (min) thermal suspension a in %
20% by weight MS in mS / cm Starch base apple 0.15 16.8 0 0 0 earthen 1 - 1 1.1 13 21 210 30 1-2 1.1 13 19.5 210 48 The RVA viscosity measurements are carried out and are presented in the table below.
Results:
[Table 11]

Tests RVA Drop (mPa. $) RVA Peak (mPa. $) Apple starch base 545,887 Earth Thermally modified starches prepared from starch 1-1 and 1-2 exhibit improved stability during the process of use compared to to the native potato starch: less viscosity setting phenomena and of retrogradation are observed when using these starches thermally modified.

Example 6: Preparation of thermally modified starches D-1 and D-2 from cassava starch 1) The alkalization of cassava starch is carried out according to the stages following:
-Prepare a suspension of cassava starch at 36.5% by weight of material dry (MS) -Prepare a sodium carbonate solution at 30% mass concentration so as to obtain a conductivity on the milk of between 4 and 7 mS / cm.
-Ensure a contact time of 0.5h -Filter and dry the cassava starch so that the conductivity final on the powder resuspended at 20% by weight of DM or lmS
2) Heat treatment The product thus obtained is heat treated in turbojets continuous of the VOMM type in series, the set point temperature of which is fixed at 210 C and configured to subject the product to a residence time of the order of 20 to 35 min, and so that the temperature difference between the setpoint and the temperature of the product at the outlet of the reactor, called Delta T, i.e.
of a value of the order of 22-27 C.
Process parameters [Table 12]
Conductivity on product Humidity after product before TC impregnation Delta T treatment exp returned to stay locker (min) thermal suspension a in %
20% by weight MS in mS / cm Starch base 0.10 14 0 0 0 cassava The RVA viscosity measurements are carried out and are presented in the table below.
Results:
[Table 14]
Tests RVA Drop (mPa. $) RVA Peak (mPa. $) Cassava starch base 470 610 Thermally modified starches prepared from starch D-1 and D-2 exhibit improved stability during the process of use compared to to the native cassava starch: less viscosity setting phenomena and retrogradation are observed when using these starches thermally modified.

Example 7: Use of thermally modified starches G and 1-2 in transparent coating (term clearcoating) of French fries potatoes.
To have crispy and tasty products that stay hot longer for a long time, said products are coated with a recipe based starch.

The tested formula is as follows:
[Table 15]
Amount Ingredients (/ 0) Starch tested 61.1 TACKIDEX C760 (pea dextrin) marketed by the applicant company Rice flour ML100 (Rickmers) 20 NaCl 5 Sodium bicarbonate 0.9 Disodium pyrophosphate 0.9 Xanthan gum F80 0., 1 In starch tested, it is understood:
- Thermally modified starch 1-2 according to example 5 - Thermally modified starch G according to example 3 - Crosslinked pea starch chemically stabilized CLEARAM LI 4000 marketed by the applicant company - Native potato starch - AVEBE PERFECTAMYL FFC potato starch di-Phosphate - Native pea starch N-735 marketed by the applicant company - Commercial thermally inhibited starch.
The process for preparing the clearcoating is as follows:
Preparing the battery - Homogenization of powders - Powder and water mixture using a kitchen aid equipped with a K blade, speed 1 for 10 min Dilution mass ratio (1 / 1.5) = 1 part powder and 1.5 part water (temperature 6-8 C) Coating fries - Drying of blanched cut potatoes - Coating and draining - The excess battery is removed using a blower - Frying 50s at 180 C
- Draining - Freezing lh and storage at -18 C
Final frying - Frying 2:30 to 3:30 at 180 C

The evaluation of the different clearcoated fries is carried out by the measures following:
1) Pick-up This measurement is part of the analyzes carried out routinely on this type.
application.
5 It consists of evaluating the quantity of battery fixed around the apple of earth after coating. The target value should be between 10 and 12%.
The% of pick-up = (final weight of the coated substrate ¨ initial weight of the substrate) / weight final coated substrate 2) Viscosity measurement 10 This measurement is also part of the analyzes carried out routinely. She consists of measuring the viscosity of the batter, the viscosity having a link direct with the pick-up. Thicker batter usually results in pick-up values more important.
This measurement is carried out using a T828 flow cup, diameter 4mmm, of 15 capacity 100mL. The target value is around 54-55s.
3) Fat measurement The transparent coating (English: clearcoating) having a direct impact on exchanges between the substrate and the oil, fat measurements and materials dryness is an indicator of the performance of the clear coating. Of them 20 repetitions are performed 4) Measurement of dry matter This measurement is carried out using a Sartorius pressure balance.
atmospheric (MA 40 moisture analyzer device).
5 Sensory characterization Sensory characterizations are subjective assessments and comments in terms of visual and texture (touch / mouth) have been carried out with an internal panel, previously trained to assess the crispness of fries.
The results obtained show that the replacement of pea starch reticle chemically stabilized with thermally modified starch conforming to the invention leads to a transparent coating (English: clearcoating) of fries remarkably equivalent.

Claims

Claims [Claim 1] A method of producing a thermally modified starch comprising the steps of:
(i) prepare a starch milk having a dry matter of between 30 and 40%, preferably between 35 and 37% by weight, (ii) add a solution of an alkaline agent to a mass concentration included between 25 and 35%, preferably 30% so as to obtain a conductivity on milk between 4 and 7 mS / cm, (iii) ensure a contact time of between 0.5 and 2 hours, (iv) filter and dry the starch milk so that the conductivity of the starch dried and resuspended at 20% by weight of dry matter, i.e.
between 0.7 and 2.5 mS / cm, (v) heating said dried starch so as to bring it to a temperature of more at 180 C for a residence time of 10 to 40 minutes, plus more preferably between 15 and 35 minutes.
[Claim 2] A method according to claim 1, characterized in that the origin of the starch is chosen from the group consisting of maize, maize waxy;
potatoes, cassava and legumes such as peas and faba bean, more preferably waxy maize, peas and faba bean.
[Claim 3] A method according to claim 1, characterized in that the agent alkali is preferably chosen from the group consisting of the hydroxide of sodium, sodium carbonate, tetrasodium pyrophosphate, orthophosphate ammonium, disodium orthophosphate, trisodium phosphate, carbonate of calcium, calcium hydroxide, potassium carbonate, and potassium hydroxide potassium, taken alone or in combination, and more preferably still sodium carbonate.
[Claim 4] A method according to claim 3, characterized in that the rise in temperature of the dry starch obtained in step (v) is carried out in from devices of the continuous turbojet type, for which the temperature of setpoint is set at more than 190 C, preferably between 195 and 240 C, and the delta T, defined as the temperature difference between the temperature of set point and the temperature of the product at the outlet of the reactor, is between and 25 C.
[Claim 5] Thermally modified starch obtainable by the method according to any one of the preceding claims.
[Claim 6] Use of a thermally modified starch produced by the process according to any one of claims 1 to 4, as an agent thickener or texturizing agent in food applications, in particular in soups, sauces, mayonnaise, in desserts such as yoghurts, fruit preparations for yoghurts, stirred fermented milks, thermized yogurts, dessert creams, drinks, prepared meals, preparations made from meat or fish, such as surimi.
[Claim 7]. Use of a thermally modified starch produced by the process according to any one of claims 1 to 4, as an agent thickener or texturizing agent in food applications, in particular as a coating agent for the preparation of transparent coating of vegetables, such as, for example, potato fries, seafood meat or even pasta for pizzas, donuts or pie bases, snacks, croquettes, cereals or breading agents.